There is a massive gulf in teacher salary across the United States. According to salary listings published by the Bureau of Labor Statistics, Alaska has the highest annual average salary for high school teachers in the country at $85,420. That is over twice the amount their colleagues make in lowest-ranked Oklahoma, where the annual salary only averages $41,880.

Pay levels are generally worst in the south of the U.S. with Louisiana ($50,700), Alabama ($49,790) and Mississippi ($46,370) all joining Oklahoma in the bottom-10. In some cases, there are even pay differencesof up to $25,000 between neighboring states. For example, high school teachers in California earn an average of $77,390 while their neighbors in Arizona take home just $48,050.

The poor salary levels and lack of education funding in Oklahoma prompted teachers to strike for nine days last month and they demanded a $10,000 pay increase over three years. The situation shows little signs of improvement with a quarter of Oklahoma City teachers leaving their jobs every year while the state is struggling to find and keep qualified replacements.